I remember watching "Erebus : The Aftermath" as a kid when I was home sick from school in about 1989/90, and being fascinated by the subject. For years and years I did a lot of reading on the subject and had a nostalgic trip down memory lane when I found the YouTube upload and the NZALPA website.
While the fundamental argument that a pilot should be aware of where he is at all times is fair, the fact is that there is scant, if any evidence to believe that Captain Collins thought he was anywhere other than over McMurdo Sound.
Several things in the story proposed at the time by ANZ simply don't make sense, and Mahon was quite justified in believing it likely that someone was trying to pull the wool over his eyes. The only thing he was censured for was stating this belief as plainly as he did - his investigation and conclusions regarding the accident were never in doubt, though the full force of the New Zealand Government and Air New Zealand's
PR operations did their best to claim that the censure for the former invalidated the latter - quite successfully it would seem, given some of the posts on this thread.
The meat of what Mahon was saying was that there was a fundamental organisational failure at ANZ, and in Civil Aviation, in the time leading up to the crash - to whit:
1. For whatever reason, the 1977 and 1978 requirement that any captain taking an Antarctic flight should first take a familiarisation flight down there was rescinded for 1979. By all accounts, ANZ simply said they weren't going to require it anymore, and Civil Aviation acquiesced.
2. While the initial, manually navigated flights did indeed have their final waypoint a route that took them over Mt. Erebus, in all cases the weather and visibility were good enough for the crew to take them off that track and fly the McMurdo Sound route. It should be noted that Mahon was of the opinion that the initial waypoint and route directly over Erebus could not be justified under any circumstances for a sightseeing flight and should never have been approved in the first place.
3. Chief Navigator Brian Hewitt of Navigation Section made a gross error when he miskeyed the waypoint - he simply did not perform the final re-check as required by the standards set by the company, and for 14 months the computerised track took every single ANZ Antarctic flight down McMurdo Sound, and because that route was very close to the military McMurdo Sound route that the line pilots had been flying visually prior to computerisation anyway - to the line pilots it seemed like a perfectly logical waypoint.
3. In any case, the only department of ANZ that continued to believe that the route went over Erebus was the Navigation Section themselves. Every single line pilot that flew the route testified to the fact that the route took them down McMurdo Sound, and at least some, if not most of the briefing materials given Captain Collins indicated that route, and not the route over Erebus. Now, here's where things get tricky - because all the hard copies of the briefing materials other than the few provided by Captain Gemmell (which could be argued supported ANZ's claims) were either lost on the mountain, lost in transit, or possibly destroyed (see the story about Captain Collins' ring binder, recovered at the site intact, yet reappearing at the commission with the pages missing). All briefing materials bar one indicated the McMurdo Sound route, or an approximation of that route - and upon cross-examination Chief Navigator Hewitt was "very surprised" that these documents indicating the McMurdo Sound route constituted part (in fact a majority) of the briefing materials.
4. Regardless of the reason - Navigation Section updated the computer track only hours before Captain Collins and his crew took TE901 off the ground and
failed to tell them. Collins may have plotted the route on the maps at home using the numbers he had -
but they were the old (incorrect) numbers. Now it could be argued here that he should have cross-checked the new numbers with the old - and logically this was an oversight. But the prevailing culture at ANZ at the time, as testified to by the line pilots, allowed pilots to safely assume that the co-ordinates given at the briefing would be the same ones they'd be flying. This right here is a major systems failure, and, Mahon (IMO rightly) considered, the fundamental cause of the accident.
5. Prior to this you had a situation whereby the national carrier and the Civil Aviation authority of New Zealand had a relationship that some would say was too cosy. And you also had Prime Minister Muldoon as the majority shareholder in the national carrier, and a personal friend of ANZ's then-CEO to boot. Had this not been the case, I suspect the reaction to Mahon's findings would have been very different.
In any case, it transpired that the minority decision by the Court Of Appeal censuring Mahon (for his language regarding the "litany of lies" remember -
not his findings), was taken by two judges who had children working for ANZ at the time. After the report was published, ANZ also released the minutes of meetings taken directly after the accident which revealed that the board and senior pilots were well aware of the discrepancy in the nav track, and yet denied this publicly and to Mahon himself - proof they were indeed lying. But because this evidence was not entered in the original Commission (ANZ took the request for documents to include those up to the time of the accident - again pretty convenient), this could not be produced either during the Appeal, or to the Privy Council.
Finally, Chippindale himself said in 1989 that Civil Aviation was actively trying to avoid a large insurance payout, and while he stood by his report, it was relevant.